The WSJ interview of David McCullough got a fair number of comments here recently (http://news.ycombinator.com/item?id=2670876 http://news.ycombinator.com/item?

The WSJ interview of David McCullough got a fair number of comments here recently (http://news.ycombinator.com/item?id=2670876 http://news.ycombinator.com/item?id=2670876), and the interview prominently mentions the claim that "Just 2% of [US high-school seniors] understand the significance of Brown v. Board of Education." This Language Log article dissects that claim.